This application describes a five-year research program that investigates individual, social, and structural influences on HIV risk and serostatus among men who have sex with men (MSM) in Bogota, Colombia. This study is of public health significance because it will contribute to knowledge concerning HIV prevalence and risk behavior in an understudied group at high risk for HIV. Moreover, it will evaluate the protection against HIV afforded by circumcision among MSM in Colombia. This application is innovative in its use of a conceptual framework that addresses HIV risk within the social and structural context. In Colombia, there are legal protections of the rights of all individuals, including gay men, while at the same time, there is ongoing civil unrest, forced displacement of large numbers of people, and homonegativity. This study investigates how such societal characteristics, as well as individuals'characteristics, influence vulnerability to HIV. The aims of the proposed study are 1) to examine structural, social, and individual factors relevant to HIV risk among MSM in Bogota;2) to estimate prevalence of HIV among MSM in Bogota;3) to explore the association between circumcision status and HIV serostatus and to investigate beliefs, knowledge, and attitudes concerning circumcision among Colombian MSM;and 4) to integrate information gained from the various research methods used and to draw conclusions that will guide the design of policies and interventions addressing HIV risk among MSM in Colombia. The research consists of three phases. Phase I involves qualitative research (12 key informant interviews, 10 focus groups, and 28 life history interviews) to explore the context of life for MSM in Bogota, including sexual behavior patterns, social networks, stigma associated with homosexuality and HIV, violence, migration, and displacement. Life history interviews will be conducted with MSM who have experienced displacement. Phase II involves quantitative research. Rapid oral HIV testing and a quantitative survey instrument will be administered with A-CASI to samples of MSM, aged 15 to 49. Social and structural data will reflect conditions in Bogota's19 localidades (localities) where participants live. Data will be used to test a model of HIV risk with both individual-level analyses and multi-level analyses (incorporating characteristics of the person and the locality of residence);to obtain estimates of HIV prevalence among MSM in the city;to examine protective effects of circumcision;and to describe attitudes and knowledge of circumcision. The pilot test includes 100 participants, and the full administration of the revised survey includes 1000 participants, all obtained through respondent-driven sampling. Phase III consists of triangulation of data and dissemination of findings. The contextualized information gained from this research will be useful in HIV prevention efforts for Colombian MSM at the societal, city, community, and individual levels. PUBLIC HEALTH RELEVANCE The proposed study will examine individual, social, and structural factors influencing HIV risk among Colombian MSM, and findings will be useful in designing targeted interventions. Elucidation of societal conditions that increase individuals'HIV vulnerability;identification of susceptible groups of people;and explication of the link between individual experiences, social/structural characteristics, and HIV risk will inform prevention efforts at multiple levels, including legal or policy changes and interventions aimed at the community or individuals.